Dry cleaning process and composition



April 17, 1962 LE ROY B. EDWARDS 3,030,172

DRY CLEANING PROCESS AND COMPOSITION Filed July 21', 1959 INV EN TOR.

4,607 5. Edward/s BY dziornays 3,030,172 DRY CLEANING PRDCESS AND COMPOSITIQN Le Roy B. Edwards, 0022 Karlov Ave, kokie, Il Filed July 27, 1959, Ser. No. 829,583 3 Claims. (Cl. (i-+142) This invention relates to improvements in the method of dry cleaning and to compositions for use in same. It relates more particularly to a modification in the .dry cleaning process whereby a consistently better cleaning operation is achieved at less cost and with considerable savings in material.

It is an object of this invention to provide an improvement in dry cleaning whereby the yield of clean garments and fabrics, based upon the consumption of cleaning materials, is greatly improved and wherein a consistently better cleaning operation is achieved.

More specifically, it is an object of this invention to improve the process of dry cleaning to increase the total number of garments and textile materials which can be cleaned per unit Volume of cleaning materials while still improving the quality of the cleaning operation thereby to achieve better cleaning at lower cost.

These and other objects and advantages of this invention will hereinafter appear and, for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the attached drawing, in which the sole FIGURE in the drawing is a schematic diagram of the dry cleaning operation.

The invention is addressed to the dry cleaning operation wherein use is made of conventional dry cleaning solvents in which the garment, textile material and the like are agitated to dissolve oily or greasy film binding dirt particles to the fabric and to remove such other particles of dirt as are present in the fabric. Such conventional dry cleaning solvents may be exemplified by volatile hydrocarbons or chlorinated hydrocarbons such as gasoline, benzene, naphtha, Stoddard solvents, carbon tetrachloride, perchlorethylene, trichlorethylene and the like and mixtures thereof,

To enhance the cleaning action, the dry cleaning solvent is usually formulated to contain a compound which is generally referred to as a dry cleaning soap or detergent which, amongst others of its characteristics, operates to decrease static and to lower surface tension. For this purpose, use can be made of water soluble alkali metal soap of fatty acids and fatty acid esters, and synthetic detergents such as alkyl aryl sulfonates, or sulfates and their salts as described in the following patents: No. 2,388,962, No. 2,327,183, No. 2,327,182, No. 2,326,772 and No. 2,271,635; sulfates of polyhydric alcohol esters as described in US. Patents No. 2,290,870 and No. 2,181,087; or compounds such as the sorbitan fatty acid esters, glycerol fatty acid esters, polyoxyethylene derivatives of sorbitan fatty acid esters, and the polyoxyalkylene fatty acid esters, such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, glyceryl monostearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate. Depending upon the type of textile that is being cleaned and the detergent or soap, such soaps may be incorporated in amounts ranging from 1-10 percent by weight of the solvent in a cleaning composition and up to equal parts by weight of the solvent in at spotting composition while the synthetic detergents may be incorporated in amounts within the range of .1-5 percent by weight of the solvent and preferably in amounts within the range of 1-5 percent by weight of the solvent in a 3,03%??? Patented Apr. 17, 1962 cleaning composition and up to 25 percent by weight in a spotting composition.

For the removal of marks or configurations called water spots which are caused by water having come into contact with the fabric to cause roughening or partial solution of the finishing material or for the removal of spots caused chiefly by water soluble substances such as perspiration, soft drinks, sugar syrup and the like, it is desirable to make use of a cleaning composition having a controlled amount of water or moisture to remove the spot without deleterious effect on the fabric, the dyestuif or finish of the fabric. Such amount of water to provide a cleaning composition can be controlled by the use of a soap or detergent having a range of tolerance for water or moisture and which is compatible with the cleaning solvent to permit the desired amount of moisture or water to be retained in the cleaning composition for the removal of oil soluble or oil water soluble water solvent soil as well as the greater amount of insoluble soil than would be possible to remove in the absence of water. The amount of water content in the cleaning composition will depend somewhat on the type and amount of detergent. It is usually employed in an amount ranging from about .l-5 percent by volume of the cleaning composition and preferably in an amount Within the range of l-S percent by weight. Generally this amount can be controlled by reference to the detergent and by the relative humidity which is maintained between -80 percent.

The foregoing describes, in general, the formulation of compositions employed in the processes'of dry cleaning fabrics and textile materials and garments which are manufactured thereof. While a dry cleaning soap or detergent is essential to the combination, the dry cleaning composition can be employed without moisture, especially where moisture is present in the fabric for removal into the solvent and especially where water spots or water soluble dirt are not otherwise present in the fabric.

For each cleaning composition, there is an optimum in the amount of detergent present depending upon the detergent, the solvent and the type of fabric that is being cleaned. It has been found that a certain amount of detergent is removed by the garment during the cleaning operation such that a composition containing an optimum amount of detergent at the beginning of the cleaning cycle will have less than the optimum amount during subsequent portions of the cycle such that the cleaning composition will become less and less effective as the cycle progresses and as additional fabrics are processed through the dry cleaning operation wherein the same cleaning composition is employed. As a result, it has been found that the removal of dirt is incomplete and that the amount of dirt removed becomes less and less in proportion with the use of the cleaning composition and in the number of cycles through which it has been employed.

Attempts have been made to make up the deficiencies by analysis of the cleaning composition to determine the extent of the deficiencies following by additions of an increment of detergents calculated to make up such deficiencies. This technique is difficult to practice and cleaners are reluctant to follow instructions with the result that the cleaning composition rapidly deteriorates with corresponding unsatisfactory results in the cleaning process. Even when carefully followed, such variations occur in the character and in the amount of detergent present in the composition during the cleaning cycle as to provide for non-uniform, if not unsatisfactory, cleaning and the yield is rather low. For example, it has been found that the yield per drum of solvent will average about 7,000 to 7,500 garments. When calculated on the basis of the expensive chlorinated solvents, the cost of raw materials per garment cleaned is rather high.

In accordance with the practice of this invention, the deficiencies described are overcome by a new concept in the use of soaps or detergents characterized by the continuous introduction of detergent as a concentrate in the cleaning composition coincident with its use in the cleaning process in an amount calculated to correspond with the amount of detergent that is removed during the cleaning operation. Such continuous additions of concentrate operate to maintain the level of detergent at the optimum concentration throughout the dry cleaning process where by maximum efliciency in cleaning is secured without deterioration of the composition. The rate of introduction of the detergent is calculated to correspond with the rate of the removal of the detergent by the fabric. Thus, once the optimum concentration of detergent has been determined, the level can be kept relatively constant throughout the cleaning process and from one cleaning cycle to another.

When additions of detergent are made continuously during the cleaning process, the number of garments capable of being processed per unit volume of cleaning composition consumed is increased far and beyond normal expectations. As previously pointed out, it has been found that the number of garments capable of being cleaned per drum of cleaning solvent consumed in the dry cleaning operation can be increased many times by comparison with the number of garments cleaned per drum by practices heretofore employed. In practice, the yield per drum of perchlorethylene is increased from 7,000 to 7,500 garments per drum to about 20,000 garments per drum when the concepts of this invention are followed.

It may be that the deviation from the optimum with a resulting deficiency in detergent leads to a more rapid deterioration of the detergent present or that removal of detergent is increased when lower concentrations are present in the cleaning composition. Whatever the reason, additions of detergent constantly to maintain the concentration at the desired level for most efiicient use apparently result in an extended life and retention of detergent in the cleaning composition whereby the number of fabrics or garments cleaned is unexpectedly increased.

This not only results in the use of less solvents and detergents, but also of considerable importance, the retention of the detergent within a desired range of concentration has been found to be effective also as means for maintaining the moisture or water at an optimum level in the cleaning composition whereby greater efiiciencies are secured in dirt removal. This means for control of moisture content may have beneficial effect on the savings of detergent in the cleaning composition whereby a very d sirable synergistic effect is secured wherein one component operates to maintain the other in balance such that the two together are more effective with less of a loss of material. The ability to control moisture content in response to the level of detergent also results in elimination of shrinkage problems and the avoidance of matting of the fibers.

Such maintenance of detergent and moisture at the desired level in combination with the cleaning solvent is effective also to provide for a better cleaning operation in less time so that a cleaner garment is secured with less wrinkle during solvent extraction. In actual experience, it has been found that many garments processed in accordance with the concepts of this invention are subjected to little, if any, wrinkling during solvent extraction whereby the garment can be removed from the tumbler and placed upon a garment hanger without the necessity of pressing the garment before wear. Equivalent results have not been possible in processes of the type heretofore employed in dry cleaning.

The addition of detergent can be made in various ways. Detergent can be introduced into the washer; or into the lines leading into or out of the washer; or detergent can be added to the storage tank or to the filtration unit through which the detergent is circulated for the removal of dirt. Introduction can be made ropwise, as by a pump operated in response to external control but it is preferred to have the means for introducing detergent responsive to the operation of the cleaning equipment to i rovide for introduction during the washing cycle thereby to maintain the desired concentration throughout the cycle. Wlr'le not equivalent, the addition of detergent can be made in response to a time control for the introduction of detergent independent of the washing cycle but in relation thereto. Solvent is continuously supplied to maintain the volume as by replacing solvent as it is removed from the system.

Having described the concepts of the invention and the unexpected advantages and improvements which are secured, illustrations will now be made of a representative system for dry cleaning in accordance with the practice of this invention.

Referring now to the drawing, the numeral 10 indicates a dry cleaning washer of the type well known to the art which is provided with the usual wheel 12 rotatably mounted therein for flushing the cleaning solvent 14 through the garments 16.

Means are provided for circulating the liquid cleaning composition through the washer including, in series, a lint and button trap 18 connected by line 2% with the bottom of the washer; a pump 22 in line 24 leading from the trap 18 to the filter 26 for forcing the cleaning liquid to and through the filter in which soil and moisture are removed from the liquid cleaning composition. A sight glass 28 is provided in the return line 3% connecting the filter with the washer for permitting visual inspection of the liquid cleaning composition entering the washer and another sight glass 32 is provided in line 24 to permit visual inspection of the liquid cleaning composition leaving the washer whereby a comparison can be made between the liquid entering and leaving the washer to determine when the dirt has been substantially completely removed from the garments.

The detergent 34 is provided in a reservoir tank 36. Detergent liquid in the desired amounts is displaced from the tank into line 38 by a displacement pump 4-0 for the introduction of detergent into line 3!) beyond the filter 26 but before the washer 10 to introduce detergent into the liquid dry cleaning composition. The displacement pump is connected for operation concurrently with the cycle of operation of the washer constantly to replace detergent removed by the garment or the filter. Instead of circulating the liquid from the filter 26 directly to the Washer 10, the filtered liquid dry cleaning composition can be returned to a reservoir from which it is fed to the washer.

As previously pointed out, line 38 through which the detergent is introduced into the dry cleaning system may be connected to the washer for a direct introduction of the additional detergent, or it may be connected to line 24 beyond the washer or to the filter 26, or to the reservoir for the constant replenishment of detergent to maintain the desired level of concentration.

As the displacement pump 4-0, use can be made of a device as described in the Edwards Patent No. 2,606,377. Instead, use can be made of other conventional liquid displacement means. Instead of operating the pump by such mechanical displacement as described in the aforementioned pateut, operation can be effected through an electrical motor operated with the pump 22 to provide for the operation of the displacement means during the cleaning cycle. The rate of introduction can be varied by adjustment of the stroke of the displacement pump or other proportioning means to increase or decrease the amount of detergent introduced into the cleaning cycle in accordance with the type of detergent, the type of fabric or the solvent system. The test for concentration can be made periodically to determine deviations from the optimum and proper adjustments as to rate of introduction can be made to compensate for such differences.

The following is given by way of illustration, but not by way of limitation, of cleaning compositions which may be used in the practice of this invention.

Example I Detergent concentrate:

5 parts by weight sorbitan monooleate 1 part by weight sorbitan trioleate 1 part by weight polyoxyethylene sorbitan monooleate Example I] Detergent concentrate:

1 part by weight polyoxyethylene sorbitan trioleatc 1 part by weight sorbitan sesquioleate Example 111 3 parts by weight ethyl phenyl phosphonate 1 part by weight sorbitan monolaurate In the use of perchlorethylene as the solvent base in the dry cleaning system, the detergent of Example I is charged in an amount of 2 parts by weight of concentrate per 100 parts by weight of solvent. To maintain the level of detergent charged in the system, concentrate of Example I is introduced into the cleaning composition during the cleaning operation at a rate of about 3 cc. of concentrate per 25 pounds of clothes being cleaned.

In a Stoddard solvent system, the concentrate of Example II is charged in an amount to provide 1.0 part of detergent for 100 parts by weight of solvent or the concentrate of Example III may be charged in an amount corresponding to 4 parts by weight per 100 parts by weight of solvent. In each instance, to maintain the charge level, the concentrate is added continuously during operation and maintains the desired level at a rate of about 510 cc. per 25 pounds of garments being cleaned.

It will be apparent from the foregoing that I have provided a new and improved means for use in a dry cleaning operation to improve the efiiciency of the dry cleaning processes and greatly to extend the life of the materials employed therein.

It will be understood that the term detergent as used herein and in the claims is meant to include soaps and various other materials as previously described. It will be further understood that changes may be made in the details of construction and operation without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. In the method of dry cleaning textile materials in an organic solvent system comprising the steps of introducing the textile material into a washer, circulating the dry cleaning solvent system through the washer and the textile material therein, filtering the dry cleaning solvent system issuing from the washer and returning the filtered dry cleaning solvent system to the Washer with sufiicient make-up solvent to maintain substantially the original volume, and removing the textile material from the washer after it has been cleaned, the improvement wherein the dry cleaning organic solvent system which is formulated to contain a detergent in combination with the organic solvent is characterized by continuously introducing detergent into the dry cleaning solvent system during the dry cleaning operation at a rate corresponding to the rate of removal during the dry cleaning operation thereby continuously to maintain the level of detergent in the dry cleaning solvent system at about the desired level for operation whereby a more efiective cleaning operation is achieved and the useful life of the solvent is materially increased.

2. The method as claimed in claim 1 in which water is present in the dry cleaning solvent system in an amount within the range of .-l-S percent by weight of the solvent system.

3. In the method of dry cleaning textile materials in an organic solvent system comprising the steps of washing the textile material in a liquid dry cleaning solvent system by circulating the solvent system through a washer containing the textile material, filtering the dry cleaning solvent system after passage through the washer and returning the filtered dry cleaning solvent system to the washer, the improvement wherein the dry cleaning solvent system which is formulated to contain a detergent in combination with the organic solvent in an amount within the range of 0.1-10 percent by weight of the solvent is characterized by continuously introducing detergent into the dry cleaning solvent system during the dry cleaning operation at a rate corresponding to the rate of detergent removed by the dry cleaning operation thereby continuously to maintain the level of detergent in the dry cleaning solvent system at about the desired level for operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,385,724 Smith et a1 July 26, 1921 2,059,475 Myers Nov. 3, 1936 2,614,026 Lascari Oct. 14, 1952 2,940,287 Henderson June 14, 1960 

1. IN THE METHOD OF DRY CLEANING TEXTILE MATERIALS IN AN ORGANIC SOLVENT SYSTEM COMPRISING THE STEPS OF INTRODUCING THE TEXTILE MATERIAL INTO A WASHER, CIRCULATING THE DRY CLEANING SOLVENT SYSTEM THROUGH THE WASHER AND THE TEXTILE MATERIAL THEREIN, FILTERING THE DRY CLEANING SOLVENT SYSTEM ISSUING FROM THE WASHER AND RETURNING THE FILTERED DRY CLEANING SOLVENT SYSTEM TO THE WASHER WITH SUFFICIENT MAKE-UP SOLVENT TO MAINTAIN SUBSTANTIALLY THE ORGINIAL VOLUME, AND REMOVING THE TEXTILE MATERIAL FROM THE WASHER AFTER IT HAS BEEN CLEANED, THE IMPROVEMENT WHEREIN THE DRY CLEANING ORGANIC SOLVENT SYSTEM WHICH IS FORMULATED TO CONTAIN A DETERGENT IN COMBINATION WITH THE ORGANIC SOLVENT IS CHARACTERIZED BY CONTINUOUSLY INTRODUCING DETERGENT INTO THE DRY CLEANING SOLVENT SYSTEM DURING THE DRY CLEANING OPERATION AT A RATE CORRESPONDING TO THE RATE OF REMOVAL DURING THE DRY CLEANING OPERATION THEREBY CONTINUOUSLY TO MAINTAIN THE LEVEL OF DETERGENT IN THE DRY CLEANING SOLVENT SYSTEM AT ABOUT THE DESIRED LEVEL FOR OPERATION WHEREBY A MORE EFFECTIVE CLEANING OPERATION IS ACHIEVED AND THE USEFUL LIFE OF THE SOLVENT IS MATERIALLY INCREASED. 